Long story, but I'm noodling over the idea of going without the net-tent or splash bivy under my tarp. Bathtub floors are a selling point of tents and I know they are supposed to help with water, spindrift and even wind to some extent. I just haven't done it before.

So, for the folks out there who cowboy camp or use tarps with just groundsheets, how do you mitigate water ingress? I know that site selection is the first place to start: don't set up in a drainage, pick a high spot, a spot where the ground can absorb some rain...

Are there more considerations or skills I need to cultivate in order to pull this off successfully? What can I do if I mess up?